You renting or buying? How often do you plan on going out? If this is a try and see how you like it scenario I would suggest renting 40# and 80# 2 speed setups from the landing.
Alternatively good price point reel to buy would be a Penn 40NLD2 Fathom. Load it with 80# braid and get yourself some 40,50,60 leader and you will be ready to fish the sinker rigs that are paying off at the moment assuming you have the rod already to back it up.
Yes, you can rent gear. Contact Seaforth Landing -(619) 224-3383 and confirm, but I'm 99% sure they rent gear. Fisherman's Landing, H&M etc. all rent gear as you are far from the only person in your position. Its fairly common honestly. Even guys that fish frequently don't necessarily have heavy gear. Explain your situation to the landing and I'm sure they will get you sorted out.
Renting is good option. Right now the fish seem to be 30-80 lbs on average. The night bite has the larger 100 lb plus on the jigs.
For fish between 30-100 lbs. a single speed reel is fine. You might have to work harder to get it to the boat compared to a 2 speed reel but it's definitely doable and has been done for years by many of us.
Besides picking up a used reel from the classifieds section on here you can look into the following options for a 40 lb rig.
SINGLE SPEED REELS (Good value for the money spent)
Avet JX (the lower gear ratio model will be easier to wind in the larger fish, but there is nothing wrong with fishing the 6.0 gear ratio JX). FYI Avet JX reels are on sale at Charkbait.
Avet JX 4.6MC $232 at charkbait
Avet JX 6.0 $199 at charkbait
Daiwa Seagate 40 $150
Daiwa Saltist 40 $260
Penn Fathom 40N $250
Shimano Torium 16 $220
TWO SPEED REELS
Shimano Speed Master 12II or 16II $250-$260
Okuma Cavalla 5II $240
Penn Fathom 40N LD 2 speed $300
There are cheaper options out there but these reels have a good reputation for not only catching fish, but for their durability to last you many years.
If i only had money to buy one I'd get the Avet JX 6.0 for $199. It's a solid reel, easy to service, and can easily handle all of the fish we have locally. 30-100 lb tuna is no problem for it.
When talking to Steve Carson (Penn West Coast rep.) on our recent Penn / Vagabond trip, he indicated that the Fathom 40N LD 2 speed is the most popular loaner reel in the long range fleet. I think that this may indicate something.