R290 top up

[Leee87]

Hi guys new to this site,
Looking for advice on r290 , I've never worked on this before in my many years I've been in the trade, but came across a fosters fridge the other day that was sat at 28 degrees, everything was working (evap/cond fans, comp etc) pressures where -11inhg low side and 50psi high side , after researching what the running pressures should be I've come to the conclusion it's low on gas, I've arranged to pressure test and recharge but the drier is in the most horrendous place as is almost impossible to replace and braze with out burning the side panel which cannot be removed,
Would anyone just Risk not changing the drier ? And please correct me if any of my assumptions on the pressures are wrong
Thanks