@ggr:
as you have mentioned nothing on tax consequences, i will assume there are not any.
here's what i would do:
the jan 18 150's have very little time premium ($1-1.50). note: the time premium in the calls is approximated well by the price of the puts, assuming dividends are zero and cost to borrow for shorting is very low.
the jan 18 300's have lots of time premium ($17-18).
the jan 18 270's have $10-11 of time premium, 260's have $8-10.
the 250 will be a relatively more liquid strike due to being a round number. the jan 250s have premium of $7-9.
so one thing i would be doing is just within the 2018's is rolling up $150s and rolling down 300's. for example: if you roll 10 150c into 250c it will cost you $7 additional in time premium. if you roll 10 300c into 250c you will save around $10 in time premium. the next savings in cost to carry will be $3 each for 20 contracts, and the amount of capital you have at risk will decline by an average of $50 per contract: you'll have $43 more at risk on the 250c vs. the 300c, but you'll have $93 less in risk going up from 150c to 250c. less risk, same exposure, less cost to carry. that part is easy.
if it were possible, i would try to consolidate the myriad 2018 positions into a single liquid strike like the 250s.
for rolling into the 2019s, generally i find it is better to wait for one of the following conditions:
1. local high price, which reduces the cost to roll forward deep in the money calls at the same strikes. i don't think tesla can peak until you see a day where it is up at least 8-10%. so i would wait for that day before i rolled. that may be why so many people are rolling now.
2. closer to expiration costs less usually. the 2019s could behave a little different due to the long duration, but one thing you can do is keep track of the spread daily and see if indeed it is going down as expiration draws nearer. this is much easier to do if you are in a single strike. right now i feel 2019s have huge premiums. you might see these come lower in december when holiday low-volume trading causes implied volatilities to contract a bit.
the current price is see to roll 250c forward a year is around $18. for the $300s it's $26.
i would prefer to keep my current contract exposure and adjust strikes to keep the amount of invested capital the same or less when i did the roll. for example: i might roll jan 18 250c into jan 19 300c on a 1-1 basis, and take some cash out.
couple other tricks that are useful for execution purposes:
1. always enter the roll order as a combined spread, so you avoid bid / ask on both sides. for example: "sell to close jan 18 150c and simultaneously buy to open jan 250c at a combined credit of $x". some brokers like fidelity have online order entry for these combined orders. most others you have to call the trading desk.
2. i prefer to start the price far away in my favor from the midpoint, and then slowly work it closer. in options with wide spreads sometimes the midpoint is not the "true midpoint". by starting at a farther away price (in your favor) and working slowly closer, you make sure you're not fat-fingering the trade at a bad price.
3. for wide spreads i may start with a 5 or 10 lot. once i know where the price is supposed to be based on my executions then i will go with the larger order.
the other tricks i would use are not feasible due to inordinately high premiums in the 2019s.