Thanks Matt and others,
I think you're right and it's just efficiency. I am curious what I can do to improve that however so thanks for the idea on the crush. I get it crushed by the shop (homebrewcompany.co.uk) so I'll ask what they suggest. I don't think I'm on the scale to by a mill yet and I'm a little paranoid about keeping grain stored due to the risk of mice in the garage.
I'm expecting to be very happy with the 5% IPA, but I'm just keen to know what I'm going to get out and work on consistency. Matt's option 1 was what I initially thought to do, but it seems like my efficiency is very, very low so I would like to improve it if possible to open up the options for what I can brew.
Interesting to hear the sparge make so much difference. I could quite easily add that step with another cheap boiler but I think I'd rather just move from BIAB if I need to spend on more vessels/gear. I guess I'd then need a longer boil to get the volume back down if I did opt for a dunk sparge?
I'll focus on the bag squeeze next brew as I know I can get more out but wasn't sure it's making much difference at that point or if it's all just as sweet as the last few ml. The only experiment I can find on it uses a hoist to drip drain the bag as the comparison so if I can't do that instead I guess a solid squeeze is the way to go. To do this I've been using a clean plastic tub to drain the bag in and press down to squeeze, transferring the resulting wort into the boiler while it's heating up.
Useful ideas as always, thanks all.