60 ma might be a little on the low side , I havent seen the full schematic , so its hard to know ,
Most likely if its a power amp , a pair of tubes in push pull it could easily draw 60ma , then you need to take account of the ac current in the choke on top of that . Either way your going to be using a sizable chunk of iron , if your drawing 60 ma dc in the circuit Id aim for a choke than can handle 90-120 ma , keeping it in and around the 600ohms dc same as field coil will help ensure conditions remain as they were inside the amp .
Theres all kinds of hidden pitfalls with the above , not least of which is finding a location for the new smoothing choke on an existing chassis , proximity and orientation of the choke in relation to the power transformer can cause unwanted interations so beware . As previously mentioned you can increase the value of the cap post choke/resistor but be sure to keep the first filter cap after the rectifier close enough to the original value otherwise your voltages will be off a signifigant amount and you risk damaging the rectifier tube .
Please also remember if your new to this , Electrolytics can store charge for days after being powered off .
If your going to probe an energised tube circuit you dont want the typical uninsulated probe tips usually found on multimeters , at very least add some extra insulation so only the very tip of the probe is exposed , a crocodile clip on the negative lead is best , then probe one handed , do Not make contact with chassis with your other hand .